1. Field of the Invention
This invention relates to the field of telephony. In particular, the invention relates to technologies for using voice over Internet Protocol (VoIP) solutions in a number of configurations to increase flexibility and reliability of call handling systems.
2. Description of the Related Art
FIG. 1 shows an example of the use of an efficiently arranged prior art system for supporting voice activated services over a telephone interface at element 130. FIG. 1 superimposes that configuration on a high level view of such a platform as illustrated by telephone 100 coupled to the telephone network 104, which is in turn coupled to a telephone gateway 107, and a phone application platform 110. In one embodiment, the phone application platform 110 can correspond to a voice portal that provides voice activated access to a variety of information including personalized content. Such a platform is described in greater detail in U.S. patent application Ser. No. 09/426,102 entitled “Method and Apparatus for Content Personalization over Telephone Interface,” now U.S. Pat. No. 6,807,574.
As FIG. 1 shows, functionally the interface with the telephone network 104 (e.g. the public switched telephone network or PSTN) is conceptually separate from the phone application platform 110, in order to achieve efficient configurations with traditional telephony equipment, the hardware to support those functions may not be as cleanly separated as shown in element 130: where there is a physical termination of one or more PSTN circuit switched calls, e.g. DS3 line in 112. A single DS3 includes 28 primary rate interfaces (PRIs), each including 24 dedicated voice channels for a total of 672 dedicated voice channels. In order to handle this number of calls, the PRIs are multiplexed out using multiplexer 114 to a collection of servers with telephony cards 116A-Z for handling the PRI and the voice communications channels therein. In one configuration, a set of Dialogic signal cards model numbers D/480SC-2TI and Antares/2000×50 from Dialogic Corporation, Parsippany, N.J., are use to handle the PRIs.
Some inefficiencies result from the preceding configuration, for example, in order to readily support “tromboning” (connections between an incoming caller and one or more parties on an outbound call) the two calls need to be handled by the same server 116. Similarly, features like conference calls have similar dependencies. Accordingly, the telephone network 104 must be programmed to distribute the voice calls across the PRIs within the DS3 to leave sufficient capacity for outbound calling purposes. Further, physical proximity between the telephone gateway 107 and the phone application platform 110 is effectively enforced by the need for the servers supporting the phone application platform 110 to be in sufficient proximity to allow termination of circuit switched calls on those servers.
FIG. 2 illustrates prior art uses of Voice over Internet Protocol (VoIP) techniques to provide telephony services. Prior to VoIP type technologies, a telephone call from the telephone 200A to the telephone 200B would be carried by a series of circuit switched connections from the local telephone network 204A to the long distance telephone network 210 and on to the local telephone network 204B before reaching the telephone 200B. Some new entrants into the long distance market have begun offering lower cost transmission through the Internet 208, and more generally packet switched networks, using suites of protocols such as voice over Internet Protocol (VoIP) and gateways such as the VoIP gateways 206A-B. Frequently, such new entrants are thought of as providing lower quality service than the circuit switched network (this is frequently the case due to the use of heavy compression as well as transmission in a best effort network). Similarly, using VoIP some new entrants encourage people to use their computers to place voice (as well as video) calls from computer to computer, e.g. computer 212A to computer 212B. Some services even allow connections from computer, e.g. computer 212A, to a telephone, e.g. telephone 200A, again in the hopes of providing cut rate services since the calling party may be able to avoid many taxes and surcharges typically imposed on long distance calling
The prior approaches to providing voice activated services have been focused on the circuit switched orientation of the telephone network. Prior packet switched approaches for handling voice communications have been characterized by an end-to-end philosophy of call placement. Accordingly, what is needed is a better configuration for handling receipt and transmission of audio from and to the telephone network 104 that provides increased flexibility while maintaining compatibility with the existing telephone network 104 by leveraging VoIP standards to provide new services and functions.